Over the course of the season, center Sean Couturier had accumulated bumps and bruises that required him to take maintenance days in an effort to rest and recover between games.

Some of those bumps came with visual evidence — on Dec. 5 against the Tampa Bay Lightning, Couturier took a puck up high and had been wearing a face shield since then in place of his standard visor. On Dec. 10 against the Vegas Golden Knights, Couturier needed stitches after a skate blade cut his wrist on a face-off.

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However, before the holiday break, general manager Chuck Fletcher explained that the extent of Couturier’s ailments has been much greater than what meets the eye. The first-line center, Fletcher said, has been dealing with “various upper- and lower-body injuries all year,” describing him as a “warrior” for continuing to play hard despite not feeling 100 percent.

The Flyers’ attempt to mend Couturier’s injuries through periodic maintenance days has come to an end. On Thursday night, the team announced that Couturier had been placed on injured reserve with an upper-body injury. The move is retroactive to Dec. 18, his last game played, against the Ottawa Senators, and he is considered week-to-week.

Couturier hasn’t looked like his Selke-Trophy-caliber self as of late, and despite being fourth on the team in points with 17, he scored only one goal in his last 19 games. However, Couturier plays every situation for the Flyers, from power play to penalty kill to taking key face-offs, and provided value to the team despite his banged-up state.

“He’s such an important part to our group, whether it’s the way he defends, the way he plays against top players,” interim head coach Mike Yeo said. “You look at some of these shifts in our defensive zone that are sort of extended shifts where we’re giving up shots, he’s a guy that wins those face-offs. He’s a guy, also, that ... the way that he plays in the defensive zone allows you to kill play quickly, get out of your zone quickly.”

Couturier missed Wednesday night’s game against the Seattle Kraken and hascbeen in COVID-19 protocols since Dec. 21. So, for a second straight night, the Flyers had to fill his two-way role against the San Jose Sharks on Thursday.

The Flyers struggled in their overtime loss, partially because of their inability to get out of their own zone. The Sharks dominated puck possession, registering 89 shot attempts to the Flyers’ 53, per Natural Stat Trick. However, Yeo isn’t using Couturier’s absence as an excuse for the team’s defensive struggles.

“We can bend a little bit at certain times,” Yeo said. “Can’t break. And guys have to step up. That’s all we can ask right now. Guys are doing that. They’re battling hard. We have to find a way to be better and that’s going to be our mindset going into L.A.”

COVID-19 protocols have stretched the Flyers thin at center, with Scott Laughton and Derick Brassard both on the list. The Flyers called upon Kevin Hayes to assume the role of first-line center, skating alongside wingers Max Willman and Joel Farabee against the Sharks. Hayes, however, has played only 13 games this season while dealing with abdominal injuries and still occasionally appears limited in his movement on the ice.

To make up for the Flyers’ lack of depth at center, Yeo has called on Claude Giroux and Morgan Frost, who have played mostly wing this season, to slide into the middle for the time being. While Frost is still coming into form as he works on the defensive aspects of his game, he’s grown more confident throughout his 12 games with the Flyers this season. That development was on display against the Sharks, in which Frost registered a goal, logged 14:41 of ice time, and played on the Flyers’ second power-play unit.

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“I think that kind of happens with a lot of guys,” Frost said after the game. “You see the puck go in or you have a good start to the game, I think your confidence rises. I’m confident in my ability regardless, but yeah, I felt pretty good tonight. It was nice to get one there and keep rolling after.”

Frost also made heads-up plays on defense — in the second period, following a long battle in the defensive zone on the boards for the puck, Frost chipped the puck to safety for defenseman Nick Seeler, who was able to clear the zone.

More help at center could be on the way, however, with Brassard and Laughton eyeing returns off the COVID list. Both entered protocols on Dec. 27, and if they are asymptomatic and can produce a negative test after five days, they could potentially return to the lineup in the near future. Even once they’re back in action, the Flyers will still need to fill Couturier’s role by committee.

“Coots is obviously a massive part of this team,” Frost said. “I think everyone kind of takes pride in filling that void and obviously miss him out there on the ice, but it’s a good opportunity for guys to step up and like I said, fill that void.”